In Sager U.S. Pat. No. 5,845,617, a rotary gear pump is disclosed having meshing gears which define spaced teeth which extend helically in the general direction of the axis of each gear rotation. A flow inlet and outlet are provided, each being positioned in the housing to permit flow of fluids substantially longitudinally of the rotation axes between the meshing gears, as the gears rotate the teeth through a tooth meshing area. As the teeth of meshing gears start to engage each other, a series of chambers are formed which shrink in size, so that liquid or gas in the chambers is correspondingly compressed and expelled laterally, while the size of each chamber becomes zero at the dead center plane of the meshing gears. Thereafter, on the downstream side of the rotating gears, beyond the dead center plane, new chambers between the meshing teeth are formed, which chambers expand as rotation continues, and form a vacuum until material flows into these chambers from the sides of the rotating gears.
The above cited Sager patent proposes the utilization of gears of this type to provide internal combustion engines and pumps.
By this invention, improvements are provided to devices of the general type similar to those disclosed in the previously cited Sager patent, having added efficiency of operation and manufacture.
By this invention, a rotary gear device is provided which comprises a housing, and at least one pair of rotatable, meshing gears positioned within said housing. The meshing gears define spaced teeth which extend helically in the direction of the axis of each gear.
A flow inlet and a flow outlet are provided in the housing to permit the flow of fluids substantially longitudinally between the meshing gears as the gears rotate said teeth through a tooth-meshing area. The teeth of the meshing gears define first chambers which shrink in size to substantially zero volume as they rotate toward a dead center plane of the rotating gears. The teeth also further define second chambers formed between the teeth which are rotating away from the dead center plane. These second chambers increase in volume as they are rotated.
In accordance with this invention, at least one of the gears comprises a ring which defines the spaced teeth of the gear. The ring is positioned about the circumference of a rotatable disc, the rotatable disc being sized and positioned to tightly position the gear teeth together with the gear teeth of the other meshing gear in the tooth meshing area, but permitting a small amount of circumferential space about other portions of the circumference between said disc and the ring. This provides a self-adjustability to the gear system that can significantly reduce wear. Preferably, it is preferred for the number of teeth in one gear ring to be different from the number of teeth of the gear with which it meshes. Particularly, the number of gear teeth of one ring may differ from the number of gear teeth of the other gear which it engages by one to three teeth. Generally, the difference in the number of teeth between the number of teeth on the gear ring and the gear with which it meshes is typically no more than about two percent of the total number of teeth on the gear ring.
By this system, the individual teeth of the gear ring will engage different teeth of the gear which it engages with each revolution of the gear ring. This can even out the wear, to provide a longer lasting, low-wearing system.
Furthermore, the rotary gear device of this invention, of similar, basic design to the above, may have a substantially fixed-volume furnace chamber to receive fluid from the first chambers of the gears as they rotate toward the dead center plane, and to provide pressurized fluid to the second chambers as they are formed adjacent to the dead center plane and rotate away therefrom. The fuel inlet provides fuel to the first chambers between the gear teeth as the gear teeth form the first chambers rotating toward the dead center plane. The exhaust outlet is positioned to receive exhaust from the second chambers between the teeth as the teeth rotate away from the dead center plane.
Also, a recycle member may be provided for receiving pressurized exhaust, and recycling some of the exhaust. The recycle member comprises a circumferential groove positioned at one end of the gear teeth in a zone rotationally beyond the dead center plane, in the area where the chambers are expanding. This groove provides exhaust from second chambers at a rotational position farther away from the dead center plane to expanding second chambers at a rotational position nearer the dead center plane. Thus, as the chambers open to highly compressed, hot gas from the fixed-volume furnace chamber, some exhaust is coming into the same chambers from the other side, to facilitate formation of a shock wave to transmit energy to power expansion of the chambers, to provide more useful work and power efficiency.
The expanding chambers naturally form a vacuum as they expand. The onrush of highly pressurized gas into a vacuum is known be a fairly inefficient process. Thus, by providing some added gas into the other end of the opening chamber by means of the circumferential groove recycle member, some gas is provided to shock, permitting formation of the shock wave. Of course, a shock wave cannot exist in a vacuum.
This shock wave serves to transmit energy to power expansion of the chambers by interaction against the walls of the gear teeth, which, in turn powers the rotation of the gears, to provide efficiency to an internal combustion engine making use of the rotating gears of this invention.
In another aspect of this invention, in an engine of similar basic design to the above, the teeth of the gears define first and second chambers between them that communicate with the entry and exit ports of the furnace chamber at specific rotational positions of the gears. The entry and exit ports are respectively positioned at opposite sides of the dead center plane of the meshing gears. One pair of the gears has teeth that are rotationally displaced relative to the teeth of an adjacent pair of meshing gears on the other side of the same furnace chamber, so that the respective first and second chambers of the gear pairs communicate with the furnace chamber ports at differing rotational positions of the overall gear assembly. As a result of this, their times of opening to the furnace chamber is not simultaneous, and great turbulence is promoted which facilitates extremely fast, and complete mixing in the furnace chamber.
The rotary gear device of this invention may preferably comprise at least four coaxially positioned pairs of meshing gears in stacks, each gear of the stack being separated by an annular groove from the adjacent, coaxial gears, and the coaxially positioned, meshing gears being sealed with a pair of end seals. Also, a furnace chamber as described may be positioned in every other groove. Such ganged sets of meshing gears can provide greatly increased efficiency to the overall engine, when compared with separate pairs of gears. Furthermore, the sealing problems are greatly simplified, since they seal each other, and only need to be further sealed with a pair of end seals at each end of the stacks of gears.
The device of this invention may be used as an internal combustion engine for vehicles, or as an efficient, compact pump. It may also be used as a chemical reactor, since reactants can be greatly compressed and heated by running the device as a pump (in the opposite direction from internal combustion). By way of advantage, dangerous, explosive reactants may be so processed, because each reaction chamber (the first and second chambers) are tiny and carry a very small amount of reactant. Thus, should an explosion take place, damage may be minimal. At the same time, because of a large number of chambers which in aggregate may number, if desired, in the hundreds or thousands as formed with these rotating gears, so that a substantial amount of reaction product can be prepared on a continuous process basis, particularly in the case of fast, high temperature and pressure reactions.